Add conversion to all missing statements

[celinval]

Implement the translation MIR -> SMIR for the missing Statements:

### Missing statements
- [ ] FakeRead
- [ ] SetDiscriminant 
- [ ] Deinit
- [ ] StorageLive
- [ ] StorageDead
- [ ] Retag
- [ ] PlaceMention
- [ ] AscribeUserType
- [ ] Coverage
- [ ] Intrinsic
- [ ] ConstEvalCounter 

[ouz-a]

I don't think rustbot works here but let's not break the convention.
@rustbot claim

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[ericmarkmartin]

should this be closed in light of rust-lang/rust#114320?